For the rhubarb orange tart, first sift flour and powdered sugar for the dough. Knead with salt and butter to a crumbly dough. Add eggs and knead until smooth and soft. Form into a ball, wrap in plastic wrap and refrigerate for at least 1 hour.
Grease a tart pan. Roll out the dough to a thickness of 2-3 mm. It should be slightly larger than the tart pan you are using so that the edges can be nicely lined as well. Place the dough in the mold and chill again for half an hour.
Prick the dough several times with a fork and bake blind at 180 °C. Let cool and remove from the mold.
In the meantime, prepare the filling. Peel the rhubarb and cut off the ends. Cut into pieces of about 1-2 cm. Bring to the boil with 100 g sugar and a little water, simmer for a few minutes and then leave to infuse for about 10 minutes. Strain and collect the liquid. Boil it down to a syrup.
Meanwhile, peel and fillet the orange. Melt remaining sugar and butter to caramel. Simmer rhubarb in it for a few minutes, then add orange and rhubarb syrup.
For the cream, boil milk with 2/3 of the sugar and vanilla pulp and pod. Beat remaining sugar with egg yolk until creamy. Stir in flour. Then stir in the milk-sugar mixture. Bring everything slowly to the boil again, stirring, and simmer briefly until bubbly. Sprinkle a thin layer of powdered sugar over the top and